Micrometer caliper



March 28, 1950 N. R. FLETCHER 2,502,038

MICROMETER CALIPER Filed NOV. 5, 1944 gm; Q@

Patented Mar. 28, 1950,

UNITED STATES PATENT OFFlCE MICBOMETER CALIPER` Norman R. Fletcher, Erie, Pa.

Application November 3, 1944, Serial No.` 561,737 1 claim. (c1. scf-141i This invention relates to. an improvement. in micrometer calipers, the prime object being to eliminate the necessity for individual feel on thev part of the. operator in the accurate use oi this type of precision measuring instrument, and to. permit. the use of the caliper on. revolving stock in machinery, such as. lathes, other. cutting machines, grinders, etc.

An important object is to simplify the structure and. keep the external appearance and form of, the instrument. within the general. design and shape approximately of that of the ordinary conventional micrometer caliper.

A further Objectis toy provide, for handling the instrument conveniently and facilitating the ready reading oiA the. indicator` element from. differentangles. oiview in the handling, and. manip ulation of the caliper in.. different.- positions. in which. it. is applied to the work in` use.

Other objects and advantages will hereinafter more fully. appear.y

An illustrative but non-.limiting practical embodiment of the invention is illustrated. in the accompanying.A drawings, in which:-

Eig-ure 1 is an elevationf of the instrument. in

edge view. of its body portion;

Figure 2. isz aside elevation and partial sectional view of the instrument;

liigure.` 3y is a fragmentaryy side elevation. of the part, of the', instrument' in. the region Where the indicator element:- is located; and

Figure 4. is: a. fragmentary sectional viewtaken en the. line 4 4 of` ligurey 2.

Referringv now to they drawingfin detailmumeral 5. designatesv generally; the bodyportion of the instrument; the sameY being substantially l-Jw shaped and' approximately irnthe same form as the; bodyV portion of the. ordinary conventional micrometer caliper. A, conventional anvil: elegmen-t, B is providedlin theusual way onone-:leg 1 of the body member 5. The opposite leg 8 of the body member 5 is bored,.ast.at.9, in-.axial alignment with thev anvil. elementV 6, in,` which. bore certainelementsof. the; improved. work measuring means, ofl thev presentv invention.. work. with longitudinallyslidable movement therein;

' An elongatedtubular member or barrel.. I.0,.pr..o,. vided with an annular collar I I. aty its lower. end, has. its lower endy portion` locatedv in'v thea bore 95 or sleeveportionof the; body 5the collarv II be-. ingy feather-keyedor. splined; to permit endwise or. longitudinal movement. but... preventing. rotation of? the. tube.. orbarrel Il). in said borey or., sleeve,- pftion A plug, I 2 having anaXialbore I 3: is` ttedtigl'ns;`

ly and held securely, in any conventional man ner, within the lower end portion of the bore or sleeve portion 9 of the body 5. The tube or barrel L0 is yieldably held normally with its end collar I I in contact with the plug I2 by aspring element I4 which is interposed between the collar portion I I anda bushing I5 which is screwed, as at I.6.,.into the upper end portion of the body bore or sleeve 9. This bushing I5 is provided with an axialbore t1 through which the. tube or barrel element I- works with an easy sliding t.

The resiliently held tube or barrel member II) of the caliper of the present invention., which supplements or is provided in place of the usual integral or xedly mounted barrel of theordinary micrometer caliper structure, has a separate sleeve f8 shrunk or otherwise xedly secured: over the present tube or barrel member le; so as to be,l in, effect, an integral. part of the tube or barrel H3. This sleeve I8 which, inv practice,4 is made of a; metalv somewhat harder thanthat of which the tube or barrel It. is made, has the. graduated longitudinal scale I9 engravedror otherwise suitably inscribed thereonand corresponding. to the similar scale which. is usually inscribed directly on the conventional integral or fixed barrel. member of the. ordinary caliper. Except. for the additional advantage 4in the minimization of wear on the barrel. Ill) due to the rotation off the manipulating thimble thereon, the barrel Ill ofthe instrument of the present invention need not have the additional sleeve I8 but have the scale I9 inscribed directly thereon." The thimble elementof the micrometer offthe present inventionr designated by the reference" numeral 2U, operates, upon the tube or barrel [Il and cooperates with theV longitudinal` scale 1.9 substantially in thefsame manner as in the. conN ventional micrometer caliper structure. That ifs to say, the inner endv portion4 of the thimbl'e is beveledofi or tapered, as at 2l, and' provided thereonwith a fractional annular scale 22.' which isf read in connection with' the scale I9.. There is some diierence, however, in the eective read#l ing of the measurement by thecooperation of the'Y two scales I9y and. 22v d'ue to the. correlated' functioning` of a special indicator element. 23'. in con; nection therewith, as will' be presently described? more fully in detail;

The` tube or. barral. IU ofV the device of the' presentinventionisirelief bored, as at 24, lthrough-'j` outrtheV major, portion. of its length from its lower end. upward the upper remainder portion' 25 `l which isv of' smaller inside diameten ifs screwj threaded`as, at 26, to receive the screw threatleti."4

upper end portion 21 of the spindle element 28. The form and provision of this spindle 28 is substantially the same as that of the ordinary spindle in the conventional micrometer caliper. That is to say, its lower portion is of substantially the same diameter as the anvil element 6 on the legy 1 of the body 5, and its upper portion of larger diameter and screw threaded, as at 21, works in the internally screw threaded portion 26 of the tube or barrel I0. The extreme upper end portion of the spindle 28 is tapered, as at 29, and received in a counterpart recess provided in the adjacent end portion 30 of the thimble 2B, where fit is securely fastened by a screw element 3| so that the spindle and thimble are rotatable together the one by the other. Thus, when the thimble 29 is rotated, turning the spindle 28 ltherewith, the spindle by its screwthreaded f1tting in the barrel I0, moves either inward or outward longitudinally in the barrel, according to the direction of rotation of the thimble.

A sector shaped recess or pocket 32 is provided in the base portion of the upper leg 8 of the body (see Figure 2). This recess or pocket 32 houses the indicator element 23 and it is provided at one side with a removable cover plate 33 (see Figure 3). As shown, the indicator element 23 comprises a pointer member or needle which is pivotally mounted, as at 34, at its inner end, with its extreme outer end portion working through or in close proximity to a slot 35 provided in the arcuate top closure 36 of the recess or pocket 32. An arcuate slot 31 (see Figure 3) is provided in the removable side cover plate 33 for viewing the indicator element 23 from that side of the instrument. For the same purpose, that is to say, viewing the indicator element 23 from the opposite side of the instrument, a corresponding arcuate slot 31' is provided in the opposite side wall of the recess or pocket 32 (see Figure 2).

The indicator element 23 is provided near its pivot with a tapered angular toe which is engaged in a substantially counterpart pinhole or recess 38 provided in the adjacent peripheral face o f the collar II of the tube or barrel member IIJ. With this provision and arrangement, and, pivotal mounting of the indicator element `23 with the pintles of its hinge mounting 34 engaged in openings or recesses provided therefor in the side plate 33 and opposite side wall of the recess or pocket 32, an endwise or longitudinal movement of the barrel I0 causes an oscillation of the indicator element 23. In the normal position of the tube or barrel IB with its collar portion in contact with the plug I 2 the indicator element 23 is in a position coinciding substantially with the ends of the slots 35 and 31, 31', closely adjacent the sleeve portion 9 .of the instrument, but when the barrel II] is vcaused to move .longitudinally so as to lift the collar portion II away from the plug I2 the indicator element 23 is accordingly swung in the direction toward the opposite ends of said slots 35, 31 and 31' At points coinciding with each other on the arcuate outer wall 36, cover plate 33 and opposite side wall of the recess or pocket 32, and approximately midway between the opposite ends of the slots in said parts, a single reference mark 39 is inscribed and the same may or may not be marked with a zero symbol, as desired. The relative position ofthe coinciding reference marks 39 in correlation to the longitudinal scale I9 on the outer sleeve member of the tube or barrel I0 of the instrument, is such that when the piece of work to be measured (designated by the reference numeral 40 in Figures 1 and 2) has the micrometer of the present invention applied thereto, the thimble 20 is turned by the operator until the inner -end of the spindle 28 moves into contact with the face of the work whose opposite face abuts the anvil 6 and without consideration as to any degree of pressure or feel on the part of the operator but merely watching the indicator element 23 and continuing rotation of the thimble 20 until the indicator element comes in coincidence or registration with one of the reference marks 39 which the operator has in sight at the time. That is to say, the correlation of the travel of the indicator element 23 with relation to the scales I9 and 22 is such that when the indicator element 23 registers or coincides with any one of the reference marks 39, which marks are in exact coincidence with each other, the extreme inner end of the thimble 20 is in exact coincidence with the particular reference line of the scale I9 for correct indication of the measurement of the piece of work 40. Should the piece of work be under-size for the dimension desired, the indicator element 23 will not have reached coincidence with the reference mark 39, or if the work should be oversize, the indicator element 23 will move beyond the reference mark 39 and toward the end of the slots 35, 31, and 31 remote from the sleeve 9 of the instrument. In this connection, it is here noted that the proportionate travel of the indicator element 23 in correlation to the scales I9 and 22, is the same for any and all measurements to be effected in an instrument of the character of the present invention of a definite size for a maximum measurement. Thus, whatever the size of the piece being measured may be, all that the operator has to do in manipulation of the instrument is to continue rotation of the thimble 20 without any regard as to the degree of pressure exerted by manual operation of the spindle 2S and exercise of expert feel in pressing the spindle upon the work, and merely observe the indicator element 23 and then cease rotation of the thimble when the indicator element reaches the reference mark 39. At this time the exact measurement of the piece of work 40 will be determined by reading the indication of the correlated scales I9 and 22. For example, should the desired thickness of the piece of work 40 be twenty hundredths (.20) or two hundred thousandths (.200) of an inch that dimension will be accordingly indicated if the piece of work is of the proper size. By the same token, under or over size of the piece of work will be noted because the reading of the scales I9 and 22 is never taken in the use of the instrument except at such time that the indicator element 23 is in registration or coincidence with the respective reference marks 39.

The provision of the present invention is to eliminate the necessity for expert individual feel in the application of the instrument to the piece of work being measured and yet obtain accurate indication of the measurements, and at the same time provide an ample measure of safety in the yieldability of the spring pressed tube or barrel I0 of the device so that the instrument may be used on rotating stock in machinery such as lathes, other cutting machines, grinders, etc. The "herein illustrated structure is but one practical adaptation of the invention, and the same evinces considerable modification within the purview of the invention as dened in the appended claim. The invention, therefore, is not limited to the specific construction and arrangement shown.

It is here noted that While the present invention is illustrated as applied to an outside type of caliper it is obvious that the invention is equal- 1y as applicable to micrometer calipers of other types and especially depth micrometers, and of many different sizes in all types.

Having thus described the invention, what is claimed is:

In a micrometer caliper, the combination with a U-shaped body portion having an anvil element on one leg thereof and having a spindle element on the' other leg thereof mounted for movement relative to said anvil element, of an indicator operatively connected to said spindle element, said indicator comprisingl av collar surrounding said spindle element and carried by the latter, said collar being provided with a recess in its peripheral face, a pointer member arranged in REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 211,975 Dickinson Feb. 4, 1879 1,526,115 Carlson Feb. 10, 1925 FOREIGN PATENTS Number Country Date 47,971 Switzerland Aug. 1, 1909 

